Name: ________________________________________________  Date: ________________

STRUCTURE OF DNA

1.      What are the three basic subunits of a nucleotide?

a.

b.

c.

2.      The _____________________ ___________________ model of DNA was proposed by Watson and Crick.

 

3.      ______________________________________ is the sugar found in DNA.

 

 

4.      The ________________________ and ____________________ alternate to make up the sides of the DNA ladder.

 

5.      The sides of the ladder are held together by _______________________________ bonds.

 

 

6.      The ____________________________ join together to make up the “rungs” of the DNA ladder.

 

7.      What are the four different kinds of bases in the nucleotides of DNA?

 

 

8.      In DNA, adenine pairs with ______________________ and _______________________ pairs with guanine.

 

9.      The nitrogen bases are held together by ________________________________ bonds.

 

 

10.  The building block units of DNA are known as _________________________________.

 

11.  DNA is duplicated in the process known as ____________________________________.

 

 

12.  During replication, each strand serves as a _______________________________ for the production of anew strand.

 

13.  Suppose a sequence of DNA is T-A-T-C-C-G-A-G-T, Write the sequence on the corresponding strand. _____________________________________________________.

 

Place the diagrams in the correct order by writing the number 1 through 3 in the line above each diagram. Answer the questions that follow.

 

 

 

 

1.      What process is shown in these diagrams?

 

2.      Which picture show the DNA unzipping? What bonds are actually broken and what causes this to happen?

 

 

3.      What is happening in the picture you labeled “2”?  How does the cell know what order to place the new nucleotides in?

 

4.      Look at the diagram labeled “3”. How do the tow DNA molecules compare?

 

 

5.      What percent of each molecule was originally from the parent molecule of DNA?

 

6.      Why is it important that exact copies of DNA be made?